Fixed wing aircraft are typically provided with side opening external passenger and cargo doors. The external doorways of most larger commercial fixed wing aircraft (e.g., such as Boeing 747, 757, 767, etc.) are sufficiently high off the ground such that external stairs, external elevator or Jetway is required for personnel (e.g., passengers and crew) access to and from the interior of the aircraft. Some passenger aircraft are provided with multiple levels such as a lower lobe and one or more passenger decks. Internal staircases between these multiple levels have often been provided to allow personnel to move between levels.
In the past, 747 aircraft have been equipped with elevators that work in flight to travel between levels within the fuselage. These prior in-flight elevators have a single hinged door opening and travel from the lower lobe to the upper deck, travel between the lower lobe and main deck, or travel between the main deck and upper deck of the 747. In one example of such elevators, the elevator car is moved up and down using a chain drive with fixed sprockets.